It's brotherly revenge gone terribly wrong: When Sean Mulcahy learned that his brother Ryan had slept with his fiancée, he slit the throat of Ryan's cat, dumped it in a ditch across the street, and then texted Ryan a photo of the grisly deed, reports the Chicago Tribune. Sean pleaded guilty to animal cruelty charges yesterday and got 30 months of probation and 150 hours of community service. As he summed it up for the judge: "It was definitely fueled by out-of-control emotions as well as alcohol." (More sibling rivalry stories.)